Information recording medium on which sector data generated from ECC block is recorded, information recording apparatus for recording sector data, and information reproduction apparatus for reproducing sector data

ABSTRACT

An information recording medium includes a management area where management information is recorded and a plurality of physical sector areas used to record a plurality of physical sector data blocks, which are generated by combining some data contained in a plurality of ECC blocks.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is base upon and claims the benefit of priority fromthe prior Japanese Patent Application No. 2000-031280, filed Feb. 7,2001, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an information recording medium onwhich sector data generated from an ECC (Error Correction Code) blockstructure is recorded. The present invention also relates to aninformation recording apparatus for recording sector data generated fromthe ECC block structure. Furthermore, the present invention relates toan information reproduction apparatus for reproducing information an arecording medium on which sector data generated from an ECC blockstructure is recorded.

2. Description of the Related Art

In recent years, the standards (physical and logical standards) forexisting read-only and rewritable DVDs have been created. The standardsdescribe an ECC block structure appended with parity codes for errorcorrection as a data structure to be recorded on an optical disk(information recording medium). In existing DVDs, data having an ECCblock structure common to both read-only and rewritable optical disks isrecorded. Also, the application standards that describe the recordingformat in the application layer upon recording AV (Audio/Video)information or stream information on existing DVDs have been created.

In the physical standards, the minimum unit of user information to berecorded on an optical disk is 2048 bytes, and this recording unit iscalled a physical sector. Data in the physical sector include a data IDthat records a sector number or the like, an error detection code IED(Data ID Error Detection code) for the data ID, user information, and anerror detection code EDC (Error Detection Code) for data in the physicalsector. As an error correction scheme for improving the reliability ofdata recorded on an optical disk, a “REED Solomon product code” schemeis adopted, and an ECC block structure appended with PI (inner-codeparity) data and PO (outer-code parity) data is formed. One ECC blockconsists of data for 16 sectors. The technique that pertains to the ECCblock structure is disclosed in Jpn. Pat. Appln. KOKAI Publication No.10-172243.

In the present specifications, data contents or data structure includinga data ID and parity data is called “data”, and user information (=Maindata) to be recorded is called “information”. Also, data contents orinformation contents directly recorded in a physical sector on anoptical disk are called “physical sector data” (=physical sector datablock) or “physical sector information”. One item of physical sectorinformation has a size of 2048 bytes.

The logical standards define the data structure associated with userinformation to be recorded on an optical disk when viewed from the hostcomputer side which is connected to an interface of an informationreproduction or recording apparatus. The minimum unit to be exchangedbetween the host computer and information reproduction or recordingapparatus is defined as a logical sector, and in the presentspecification, the contents of user information corresponding to thelogical sector are called logical sector information. The logical sectorinformation has a size of 2048 bytes in correspondence with that of thephysical sector information.

The contents of the logical sector information basically match those ofthe physical sector information. However, since the physical layerdefined in the physical standard and the logical layer defined in thelogical standard are different layers, the contents of the physicalsector information may be different from those of the logical sectorinformation in practice. That is, the host computer and informationreproduction or recording apparatus exchange information using 2048-bytelogical sector information as a minimum unit, and information obtainedby processing this logical sector information may be recorded asphysical sector information on an optical disk.

The minimum unit of video object information or audio object informationtransferred between the host computer and information reproduction orrecording apparatus is also 2048 bytes in correspondence with thelogical sector size. According to the application standards, videoobject information and audio object information are broken up into 2048bytes, and are multiplexed in the format of a pack structure as aminimum unit upon being recorded on an optical disk. That is,audio/video information to be recorded on a recording medium issegmented along the time axis, and video packs that store video objectinformation and audio packs that store audio object information aredistributed while being mixed. In this case, the video or audio packinformation itself corresponds to the contents of the logical sectorinformation.

The minimum unit of recording stream information is called an SOBU(Stream Object Unit), and one SOBU size is defined to be 32 logicalsectors or 2 ECC blocks.

In existing DVDs, error correction can be made up to a maximum bursterror length of 6 mm on an optical disk. In next-generation DVDs, thedata bit length on an optical disk (recording medium) becomes smallsince the data recording density increases. Assume that the data bitlength is proportional to the wavelength of light used in an opticalhead of the reproduction or recording/reproduction apparatus, and isinversely proportional to NA (Numerical Aperture). In this case, if thenext-generation DVD has an optical wavelength of 405 nm and NA=0.85compared to the existing DVD having an optical wavelength of 650 nm andNA=0.65, the error-correctable burst error length on an optical disk(recording medium) is considerably reduced to 2.9 mm.6×(405÷650)×(0.65÷0.85)=2.9

Therefore, the next-generation DVD requires a technical means forassuring an error-correctable burst error length of 6 mm or more as inthe current DVD.

When the correctable burst error length is greatly improved for thenext-generation DVD while exploiting the REED Solomon product codetechnique as the ECC block structure, the following problems (1) to (2)are posed, and it is impossible to greatly improve the correctable bursterror length by only changing the size of the REED Solomon product codeof the existing DVD.

(1) The maximum size of a REED Solomon product code that corrects errorsfor respective unit bytes is limited to 256 rows×256 columns. In theexisting DVD, the maximum size is 208 rows×182 columns. The existing DVDhas an optimal structure within the limit range of 256 rows×256 columns,and it is difficult to greatly improve the correctable burst errorlength by merely changing the size.

(2) The main data information encoding efficiency cannot be greatlyreduced compared to the existing DVD. It is possible to improve thecorrectable burst error length by increasing the PO size in an ECCblock. But when this is done, redundancy which depends on the PO sizeincreases and the main data information encoding efficiently dropsconsiderably. The existing DVD has main data information encodingefficiency of 87% as well as redundant data such as a data ID and thelike in the physical data. Hence, in the next-generation DVD, anencoding efficiency of around 87% needs to be assured.

(3) An appropriate physical data structure must be guaranteed. As amethod of greatly improving the correctable burst error length and ofassuring high main data information encoding efficiency, a method oflargely increasing the PO size and reducing the PI size accordingly maybe readily devised. However, in order to assure high-speed data accesson an optical disk, the data ID must be arranged at the head in thephysical sector data, and an interleaved arrangement of PO data inrespective physical sectors is required for this purpose. However, toattain this, it becomes difficult to change the PO size to an arbitraryvalue.

BRIEF SUMMARY OF THE INVENTION

It is an object of the present invention to provide an informationrecording medium, information recording apparatus, and informationreproduction apparatus which can solve the aforementioned problems.

In order to solve the aforementioned problems and to achieve the aboveobject, an information recording medium, information recordingapparatus, and information reproduction apparatus of the presentinvention have the following arrangements.

(1) An information recording medium of the present invention comprises amanagement area where management information is recorded, and aplurality of physical sector areas used to record a plurality ofphysical sector data blocks, which are generated by combining some datacontained in a plurality of ECC blocks.

(2) An information recording apparatus of the present inventioncomprises generation section configured to generating a plurality of ECCblocks, and recording section configured to generating a plurality ofphysical sector data blocks by combining some data contained in theplurality of ECC blocks, and recording the plurality of physical sectordata blocks on a plurality of physical sector areas on the informationrecording medium.

(3) An information reproduction apparatus of the present inventioncomprises read-out section configured to reading out the plurality ofphysical sector data blocks from the plurality of physical sector areason the information recording medium, and reproduction section configuredto reproducing data by generating the plurality of ECC blocks from theplurality of readout physical sector data blocks.

Additional objects and advantages of the invention will be set forth inthe description which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. The objectsand advantages of the invention may be realized and obtained by means ofthe instrumentalities and combinations particularly pointed outhereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention, andtogether with the general description given above and the detaileddescription of the embodiments given below, serve to explain theprinciples of the invention.

FIG. 1 shows the data structure of physical sector data generated from aplurality of ECC blocks, the relationship between physical sectorinformation and logical sector information, and the like;

FIG. 2 shows the data structure of physical sector data recorded on aninformation recording medium, and the relationship between a pluralityof physical sector data and a plurality of (two) corresponding ECCblocks;

FIG. 3 shows the data structure of an ECC block upon completion of rowinterleave when one sector data consists of an odd number of rows;

FIG. 4 shows the data structure of physical sector data generated from asingle ECC block, the relationship between physical sector informationand logical sector information, and the like;

FIG. 5 shows the data structure of physical sector data recorded on aninformation recording medium, and the relationship between a pluralityof physical sector data and a single corresponding ECC block;

FIG. 6 is a schematic block diagram showing the arrangement of aninformation recording/reproduction apparatus according to an embodimentof the present invention;

FIG. 7 is a flowchart for explaining generation of an ECC block andrecording of physical sector data;

FIG. 8 shows the data structure of sector data when one sector data isformed of an odd number of rows;

FIG. 9 shows an example of re-arrangement of sector data when one sectordata is formed of an odd number of rows;

FIG. 10 shows the data structure of sector data when one sector data isformed of an odd number of rows;

FIG. 11 shows a state wherein the sector block shown in FIG. 10 ishorizontally segmented into two blocks, and outer and inner code partiesare appended to the respective blocks;

FIG. 12 shows the data structure of physical sector data generated froman ECC block upon completion of row interleave shown in FIG. 3;

FIG. 13 shows a state wherein data contained in physical sector dataundergoes zigzag recording;

FIG. 14 shows examples of the arrangement of an outer code (PO) inphysical sector data;

FIG. 15 shows the data structure of an ECC block upon completion of rowinterleave when one sector data is formed of an even number of rows;

FIG. 16 shows the data structure of sector data when one sector data isformed of an even number of rows;

FIG. 17 shows an example of re-arrangement of sector data when onesector data is formed of an even number of rows;

FIG. 18 shows the data structure of sector data when one sector data isformed of an even number of rows;

FIG. 19 shows a state wherein the sector block shown in FIG. 18 ishorizontally segmented into two blocks, and inner and outer codeparities are appended to the respective blocks; and

FIG. 20 shows the data structure of physical sector data generated froman ECC block upon completion of row interleave shown in FIG. 15.

DETAILED DESCRIPTION OF THE INVENTION

Preferred embodiments of the present invention will now be describedwith reference to the accompanying drawings.

Basic features of the present invention are as follows.

1) Physical sector data to be recorded on an optical disk is segmentedinto small pieces, and segmented data is sequentially arranged(interleaved) in n (n is a positive value equal to or larger than 2) ECCblocks.

2) It is devised to always arrange the data ID at the head position ofeach physical sector data before or after the interleave process. As aresult, even when access is made for respective physical sectors,address information can be quickly read out, and high-speed access canbe attained.

This embodiment exemplifies a case of “n=2”, but the contents of thepresent invention are not limited to this, and can be applied to a caseof n=3 or n=4.

As a method of arranging one physical sector data in a plurality of ECCblocks, the present invention has proposed the following two methods.

Method 1: Physical sector information matches logical sectorinformation. One physical sector data is segmented into rows includingPI, the data for respective rows are respectively assigned to n (n≧2)ECC blocks, and the total of the number of rows including PI in onephysical sector data and the number of PO rows is an integer multiple ofn.

Method 2: All pieces of information in one logical sector are containedin a single ECC block. Logical sector data contained in different ECCblocks undergo an interleave process by alternately exchanging rows ofthese blocks for respective rows, and a data arrangement obtained as aresult of that process is recorded on an optical disk as physical sectordata.

An outline of method 1 will be explained first using FIGS. 1 and 2.

An optical disk (information recording medium 9) has a physical sectorarea 9 a and management area 9 b. The management area 9 b recordsmanagement information. Data recorded in the physical sector area 9 awill be described below. AV information or stream information, which istransferred continuously, is broken up into small pieces, which areconverted into pack structures appended with pack headers, and thesepacks are recorded on a plurality of physical sector areas 9 a assuredon the optical disk. More specifically, as shown in (a) of FIG. 1, videoinformation and audio information are transferred while being arrangedalong the time axis in the form of video packs 1-0 to 1-3, and audiopacks 2-0 and 2-1. Each of the video packs 1-0 to 1-3 and audio packs2-0 and 2-1 has a data sized of 2048 bytes, which matches the logicalsector information size. The video packs 1-0 to 1-3 and audio packs 2-0and 2-1 are abstractly handled as a plurality of pieces of logicalsector information 3-0 to 3-31 in the logical layer, as shown in (b) ofFIG. 1. (that is, examples of practical contents of the plurality ofpieces of logical sector information 3-0 to 3-31 correspond to videopacks 1-0 to 1-3 and audio packs 2-0 and 2-1). In method 1, sincephysical sector information and logical sector information match, thesepieces of information are handled as a plurality of pieces of physicalsector information 4-0 to 4-31, as shown in (c) of FIG. 1. As will bedescribed in detail later, each item of physical sector information (4-0to 4-31) has the following configuration. That is, 4 byte PIDinformation, 2-byte IED information, and a 10-byte reserve field (thesize in an existing DVD is 6 bytes) are arranged at the head of eachinformation, and a 4 byte EDC is arranged at the end of information(data 0-0-0 to data 0-0-5). After that, that sequence is broken up into188-byte data (data each of data 0-0-0 to data 0-0-5), error correctionPI (inner-code parity) data (PI0-0-0 to PI0-0-5) is appeded to every188-byte data, and this data is arranged in turn as shown in (d) ofFIG. 1. In odd-numbered physical sector data (physical sector data 5-0),PO (outer-code parity) data (PO0) is arranged at the end of data tocomplete physical sector data 5.0. The present invention ischaracterized in that even-numbered physical sector data (physicalsector data 5-1) has a structure in which PO data (PO1) is arranged inthe second column from the end of data, and data 1-1-5 and PI data (PI11-5) are arranged at the end of the even-numbered physical sector data(as will be described in detail later). Physical sector data 5-0 to5-31, which is completed in this manner, is recorded on the physicalsector areas 9 a an the optical disk (information recording medium 9) inaccordance with the order it is arranged, as shown in (e) of FIG. 1. Onephysical sector data item is recorded on one physical sector area 9 a.

As shown in (f) and (g) of FIG. 2, one physical sector data 5-0 item isformed as a combination of data in two different ECC blocks 8-0 and 8-1.More specifically, data in the physical sector data 5-0 is finely brokenup into 200-byte data, and 188-byte data 0-0-0 and PI data 0-0-0 arearranged in the first row in the ECC block 8-0. Next 188-byte data 0-1-0and PI 0-1-0 in the physical sector data 5-0 are arranged in the firstrow in the ECC block 8-1. Furthermore, the next 188-byte data 0-0-1 andPI data 0-0-1 are arranged in the second row in the ECC block 8-0. Of POdata in the ECC block 8-1, the first 200 bytes are inserted in the sixthrow in the ECC block 8-1 as PO0. As a result, data from data 0-0-0 toPO0 form the physical sector data 5-0.

First data 1-0-0 and PI 1-0-0 that follow the first data in the nextphysical sector data 5-1 are arranged in the seventh row in the ECCblock 8-0, as shown in (f) of FIG. 2. Of PO data in the ECC block 8-0,the first 200-byte data is arranged as PO1 in the 12th row in the ECCblock 8-0. In this way, PO data (PO0, PO1) for respective rows (200bytes) is arranged at equal intervals for the respective physical sectordata 5-0 to 5-31, and the arrangement positions have a difference of onephysical sector data between a pair of ECC blocks 8-0 and 8-1.

The detailed structure in the ECC blocks 8-0 and 8-1 shown in (f) and(g) of FIG. 2 will be explained below with reference to FIG. 3.

FIG. 3 shows a combined state of two, right and left (for each 200-bytecolumn) ECC blocks. Each ETC block has a structure in which 12-byte PIdata is appended every 188 bytes, and PO data for 16 rows is appended.The PO data for 16 rows is decomposed into row data item, each of whichis interleaved and inserted at every 12-row positions. The hatchedportion of 200-byte columns per row in FIG. 3 means interleaved andinserted PO data.

The user information size assigned per sector is 2048 bytes as in anexisting DVD, and information having the same contents as those oflogical sector information recognized in the application layer is set aseach item of physical sector information (main data). Four-byte data IDinformation, 2-byte IED information, and a 10-byte reserve field (thesize in an existing DVD is 6 bytes) are arranged at the head of 2048bytes of the physical sector information, and 4-byte EDC data isarranged at the end of the physical sector information, thus forming allthe data of a physical sector.

Since one physical sector data is interleaved across two small ECCblocks, an error-correctable burst error length can be improved tonearly twice that of the prior art. That is, one item of physical sectordata is broken up into 188-byte data items, each of which forms one rowdata by appending 12-byte PI data (since the existing PI size is 10bytes, and is increased to 12 bytes, error correction performance perrow can be improved), and this row data is alternately and sequentiallyarranged in right and left different ECC blocks. This embodiment ischaracterized in that data (data sector) in one physical sector has anodd number of rows, i.e., 11 rows, as shown in FIG. 3. Since the datasector is made up of an odd number of rows, the total number of rows canbe even upon inserting one PO row in each physical sector, and the POrow can be properly inserted in two ECC blocks without forming an oddrow.

PID information is always arranged at the head position (upper leftcorner position in FIG. 3) of each physical sector, and the PO insertpositions are devised to allow efficient interleave insertion of POdata, as shown in FIG. 3. That is, PO data is arranged at the last rowposition of an even sector, and PO data is arranged at the second rowposition from the end of the sector in an odd sector. As a result, POdata is arranged in a single ECC block, and all physical sectors canhave the same data size.

An outline of method 2 will be explained below using FIGS. 4 and 5.

As in method 1, AV information or stream information is stored in theform of packs 1-0 to 1-3 and 2-0, as shown in (a) of FIG. 4, and theinformation contents of the packs 1-0 to 1-3 and 2-0 correspond to aplurality of pieces of logical sector information 3-0 to 3-16. For theplurality of pieces of logical sector information 3-0 to 3-16 obtainedat that time, ECC blocks 7-0 and 7-1 are formed and PI information(PI0-0-0 to PI16-1-1) and PO information (PO0-0, PO1-0) are inserted bythe same method as in the conventional DVD standards ((c) of FIG. 4).

A large characteristic feature of the present invention lies in thatprocesses from the state in (b) of FIG. 4 until (c) of FIG. 4, i.e.,appending of data ID information, IED information, a reserve field, andEDC information and an insert process of PI information (PI0-0-0 toPI16-1-1) and PO information (PO0-0, P01-0) are the same as in those ofthe conventional DVD (the numbers of data byes are also the same).Therefore, the structures in the ECC blocks 7-0 and 7-1 shown in (f) and(g) of FIG. 5 perfectly match the conventional DVD standards as well asthe values of various numbers of data byes. As a result, some of the ECCblock generation process (generation of PI and PO, and the like) anderror correction process in a reproduction apparatus orrecording/reproduction apparatus having compatible functions between theexisting DVD and next-generation DVD can be used in common to those uponusing an existing DVD disk (medium), and the processing routines andcircuits of the reproduction apparatus or recording/reproductionapparatus having compatible functions between the existing DVD andnext-generation DVD can be simplified.

In order to improve an error-correctable burst error length byinterleaving data in physical sector data 5-0 and 5-16 between the twoECC blocks 7-0 and 7-1, method 2 of the present invention executes anexchange process between data rows and PI rows (data 0-0-1 and PI0-0-1,and data 16-1-1 and PI16-1-1) located at the even-numbered row positionsof logical sector data at identical positions (having the same rownumbers) in the neighboring ECC blocks 7-0 and 7-1, as shown in (d) ofFIG. 4. Data ID information that contains sector address information isarranged in the first row in each logical sector data. Hence, when onlyan exchange process between data rows and PI rows at the even-numberedrow positions is done, and an exchange process between data rows and PIrows at odd-numbered row positions is inhibited, arrangement of the dataID information that contains sector address information at the headpositions in the physical sector data 5-0 and 5-16 shown in (d) of FIG.4 is guaranteed. Each of the logical sector data items 6-0 and 6-16always includes 12 rows (an even number of rows) of data and PI rows.Hence, by exchanging data and PI rows at the even-numbered row positionsin the logical sector data items 6-0 and 6-16 according to theaforementioned rules, the positions of PO information (PO0-0, PO1-0) inthe logical sector data items 6-0 and 6-1 and ECC blocks 7-0 and 7-1remain unchanged without being exchanged. For this reason, the appendingprocess of PO information and error correction process are facilitated.The physical sector data items 5-0 and 5-16 generated in this way arerecorded on the physical sector areas 9 a on an optical disk(information recording medium 9) in accordance with the order data inthe physical sector data items 5-0 and 5-16 are arranged. One physicalsector data is recorded on one physical sector area 9 a.

An example of an information recording/reproduction apparatus(information recording apparatus or information reproduction apparatus)will be explained below using FIG. 6.

1. Function of Information Recording/Reproduction Apparatus

1-1. Basic Function of Information Recording/Reproduction Apparatus

An information recording/reproduction apparatus executes the followingprocesses. That is,

-   -   the apparatus records new information or rewrites (or erases)        information at a predetermined position on the information        recording medium 9 using a focused beam spot; and    -   the apparatus reproduces already recorded information from a        predetermined position on the information recording medium 9        using a focused beam spot.        1-1-1. Basic Function Achieving Means of Information        Recording/Reproduction Apparatus

As means for achieving the above basic functions, the informationrecording/reproduction apparatus executes the following processes. Thatis,

-   -   the apparatus traces a focused beam spot along tracks (not        shown) on the information recording medium 9;    -   the apparatus switches recording/reproduction/erasure of        information by changing the amount of light of a focused beam        spot with which the information recording medium 9 is        irradiated; and    -   the apparatus converts an externally input recording signal d        into an optimal signal to record it at high density and with a        low error rate.        2. Structure of Mechanism Portion and Operation of Detection        Portion        2-1. Basic Structure of Optical Head 202 and Signal Detection        Circuit        2-1-1. Signal Detection by Optical Head 202

The optical head 202 basically comprises a semiconductor laser elementas a light source, a photodetector, and an objective lens. A laser beamemitted by the semiconductor laser element is focused on the informationrecording medium 9 via the objective lens. The laser beam reflected by alight reflection film or light reflective recording film of theinformation recording medium 9 is photoelectrically converted by thephotodetector. A detection current obtained by the photodetectorundergoes current-voltage conversion by an amplifier 213 to obtain adetection signal. This detection signal is processed by afocusing/tracking error detection circuit 217 or binarization circuit212. In general, the photodetector is divided into a plurality ofphotodetection regions, which individually detect changes in the amountof light with which the respective photodetection regions areirradiated. Respective detection signals undergo sum/differencecalculations by the focusing/tracking error detection circuit 217, thusdetecting focusing and tracking errors. In this way, a change in theamount of light reflected by the light reflection film or lightreflective recording film of the information recording medium 9 isdetected, thereby reproducing a signal on the information recordingmedium 9.

2-1-2. Objective Lens Actuator Structure

The objective lens that focuses a laser beam emitted by thesemiconductor laser element on the information recording medium 9 ismovable in two axis directions in accordance with an output current froman objective lens actuator driving circuit 218. The objective lensmoves:

-   -   in a direction perpendicular to the information recording medium        9 to correct focusing errors; and    -   in the radial direction of the information recording medium 9 to        correct tracking errors.

Such an objective lens moving mechanism is called an objective lensactuator (not shown).

2-2. Rotation Control System of Information Recording Medium 9

The information recording medium 9 is mounted on a rotary table 221which is rotated by the driving force of a spindle motor 204. Therotational speed of the information recording medium 9 is detected basedon a reproduction signal obtained from the information recording medium9. That is, the detection signal (analog signal) output from theamplifier 213 is converted into a digital signal by the binarizationcircuit 212, and a PLL circuit 211 generates a constant period signal(reference clock signal) based on that digital signal. An informationrecording medium rotational speed detection circuit 214 detects therotational speed of the information recording medium 9 using thissignal, and outputs the detection value.

A correspondence table of the information recording medium rotationalspeed which corresponds to the radial position where data is reproducedor recorded/erased on the information recording medium 9 is pre-storedin a semiconductor memory 219. When a reproduction position orrecording/erasure position is determined, a controller 220 sets a targetrotational speed of the information recording medium 9 by looking upinformation recorded in the semiconductor memory 219, and sends thatvalue to a spindle motor driving circuit 215.

The spindle motor driving circuit 215 calculates the difference betweenthis target rotational speed and the output signal (current rotationalspeed) of the information recording medium rotational speed detectioncircuit 214, and supplies the driving current corresponding to thatdifference to the spindle motor 204, thus controlling the rotationalspeed of the spindle motor 204 to be constant. The output signal fromthe information recording medium rotational speed detection circuit 214is a pulse signal having a frequency corresponding to the rotationalspeed of the information recording medium 9, and the spindle motordriving circuit 215 controls both the frequency and pulse phase of thissignal.

2-3. Optical Head Moving Mechanism

To move the optical head 202 in the radial direction of the informationrecording medium 9, an optical head moving mechanism (feed motor) 203 isprovided.

3. Functions of Respective Control Circuits

3-1. Focused Beam Spot Trace Control

In order to perform focusing or tracking error correction, a circuit forsupplying a driving current to the objective lens actuator in theoptical head 202 in accordance with the output signal (detection signal)from the focusing/tracking error detection circuit 217 is the objectivelens actuator driving circuit 218. This circuit 218 includes a phasecompensation circuit for improving characteristics in correspondencewith the frequency characteristics of the objective lens actuator toattain quick response of objective lens movement up to thehigh-frequency range.

In response to a command from the controller 220, the objective lensactuator driving circuit 218 executes:

-   -   an ON/OFF process of focusing/tracking error correction        operation (focus/track loop);    -   a process for moving the objective lens at low speed in a        direction (focus direction) perpendicular to the information        recording medium 9 (executed when focus/track loop is OFF); and    -   a process for moving a focused beam spot to a neighboring track        by slightly moving in the radial direction (direction to cross        tracks) of the information recording medium 9 using a kick        pulse.        4. Various Operations Associated with Control System of        Mechanism Portion        4-1. Startup Control

When the information recording medium 9 is mounted on the rotary table221 and startup control is started, the processes are executed inaccordance with the following sequence.

1) The controller 220 sends a target rotational speed to the spindlemotor driving circuit 215, which supplies a driving current to thespindle motor 204, thus starting rotation of the spindle motor 204.

2) At the same time, the controller 220 issues a command (executioncommand) to the feed motor driving circuit 216, which supplies a drivingcurrent to the optical head driving mechanism (feed motor) 203, thusmoving the optical head 202 to the innermost peripheral position of theinformation recording medium 9. It is confirmed if the optical head 202has reached an inner peripheral portion beyond the information recordingregion on the information recording medium 9.

3) When the spindle motor 204 has reached the target rotational speed,that status (status report) is output to the controller 220.

4) A semiconductor laser driving circuit 205 supplies a current to thesemiconductor laser element in the optical head 202 in correspondencewith a reproduction light amount signal sent from the controller 220 toa recording/reproduction/erasure control waveform generation circuit206, thus starting laser emission.

Note that an optimal irradiation light amount upon reproduction variesdepending on the types of information recording media 9. Upon startup,the lowest irradiation light amount value of those values is set.

5) The objective lens actuator driving circuit 218 controls to move theobjective lens (not shown) in the optical head 202 to a positionfarthest from the information recording medium 9, and make the objectivelens slowly approach the information recording medium 9 in accordancewith a command from the controller 220.

6) At the same time, the focusing/tracking error detection circuit 217monitors a focusing error amount, and outputs status to the controller220 when the objective lens has approached an in-focus position.

7) Upon receiving that status, the controller 220 issues a command tothe objective lens actuator driving circuit 218 to enable the focusloop.

8) The controller 220 issues a command to the feed motor driving circuit216 while the focus loop is ON to slowly move the optical head 202toward the outer periphery of the information recording medium 9.

9) At the same time, a reproduction signal from the optical head 202 ismonitored. When the optical head 202 has reached the recording region onthe information recording medium 9, the controller 220 stops movement ofthe optical head 202, and issues a command to the objective lensactuator driving circuit 218 to enable the track loop.

10) An “optimal light amount upon reproduction” and “optimal lightamount upon recording/erasure” recorded on the inner peripheral portionof the information recording medium 9 are reproduced, and are recordedin the semiconductor memory 219 via the controller 220.

11) Furthermore, the controller 220 sends a signal corresponding to that“optimal light amount upon reproduction” to therecording/reproduction/erasure control waveform generation circuit 206,thus re-setting the emission amount of the semiconductor laser elementupon reproduction.

12) The emission amount of the semiconductor laser element uponrecording/erasure is set in correspondence with the “optimal lightamount upon recording/erasure” recorded on the information recordingmedium 9.

4-2. Access Control

4-2-1. Reproduction of Access Destination Information on InformationRecording Medium 9

Information that indicates the locations and contents of informationrecorded on the information recording medium 9 varies depending on thetypes of information recording medium 9, and is generally recorded indirectory management regions, navigation packs, or the like in theinformation recording medium 9. Note that the directory managementregions are recorded together in the inner or outer peripheral region ofthe information recording medium 9. On the other hand, the navigationpack is contained in a VOBS (Video Object Set) complying with the datastructure of a PS (Program Stream) of MPEG2, and records informationindicating the location of the next video data.

When specific information is to be reproduced or recorded/erased,information in the above-mentioned region is reproduced, and an accessdestination is determined based on the reproduced information.

4-2-2. Coarse Access Control

The controller 220 calculates the radial position of the accessdestination, and detects the distance between that position and thecurrent position of the optical head 202. As for the moving distance ofthe optical head 202, velocity curve information that allows the head toreach the target position within a shortest period of time is stored inadvance in the semiconductor memory 219. The controller 220 reads thatinformation, and controls movement of the optical head 202 by thefollowing method in accordance with the velocity curve. The controller220 issues a command to the objective lens actuator driving circuit 218to disable the track loop, and then controls the feed motor drivingcircuit 216 to start movement of the optical head 202. When the focusedbeam spot has crossed a track on the information recording medium 9, thefocusing/tracking error detection circuit 217 generates a tracking errordetection signal. Using this tracking error detection signal, therelative velocity of the focused beam spot with respect to theinformation recording medium 9 can be detected. The feed motor drivingcircuit 216 calculates the difference between the relative velocity ofthe focused beam spot obtained from the focusing/tracking errordetection circuit 217, and target velocity information sent from thecontroller 220, and feeds back that result to the driving current to besupplied to the optical head driving mechanism (feed motor) 203, thusmoving the optical head 202. As described in “optical head movingmechanism”, a frictional force always acts between a guide shaft andbushing or bearing. When the optical head 202 moves at high speed,dynamic friction acts. However, since the moving velocity of the opticalhead 202 is low at the beginning of movement and immediately beforestop, static friction acts. At that time, since the relative frictionalforce increases, the amplification factor (gain) of a current to besupplied to the optical head driving mechanism (feed motor) 203 isincreased in response to a command from the controller 220 (especially,immediately before stop).

4-2-3. Fine Access Control

When the optical head 202 has reached the target position, thecontroller 220 issues a command to the objective lens actuator drivingcircuit 218 to enable the track loop. The focused beam spot reproducesan address or track number of that portion while tracing along a trackon the information recording medium 9. The current focused beam spotposition is detected from that address or track number, and thecontroller 220 calculates the number of error tracks from the reachedtarget position and informs the objective lens actuator driving circuit218 of the number of tracks the focused beam spot is required to move.When the objective lens actuator driving circuit 218 generates a pair ofkick pulses, the objective lens slightly moves in the radial directionof the information recording medium 9, thus moving the focused beam spotto a neighboring track. In the objective lens actuator driving circuit218, the track loop is temporarily disabled, and after kick pulses aregenerated a given number of times corresponding to the information fromthe controller 220, the track loop is enabled again. Upon completion offine access, the controller 220 reproduces information (address or tracknumber) at the position where the focused beam spot is tracing, andconfirms if it has accessed a target track.

4-3. Continuous Recording/Reproduction/Erasure Control

As shown in FIG. 6, a tracking error detection signal output from thefocusing/tracking error detection circuit 217 is input to the feed motordriving circuit 216. “Upon startup control” and “upon access control”mentioned above, the controller 220 controls the feed motor drivingcircuit 216 not to use the tracking error detection signal. After it isconfirmed that the focused beam spot has reached the target track byaccess, some components of the tracking error detection signal aresupplied as a driving current to the optical head driving mechanism(feed motor) 203 in response to a command from the controller 220. Thiscontrol continues during the period in which a reproduction orrecording/erasure process is done continuously. The informationrecording medium 9 is mounted so that its central position has a slighteccentricity from that of the rotary table 221. When some components ofthe tracking error detection signal are supplied as a driving current,the entire optical head 202 slightly moves in correspondence with theeccentricity. When the reproduction or recording/ erasure process iscontinuously done for a long period of time, the focused beam spotposition gradually moves toward the outer or inner periphery. When somecomponents of the tracking error detection signal are supplied as adriving current to the optical head moving mechanism (feed motor) 203,the optical head 202 gradually moves toward the outer or inner peripheryin correspondence with that current. In this manner, the load ontracking error correction of the objective lens actuator is reduced,thus attaining a stable track loop.

4-4. End Control

When a series of processes are complete and the operation is to beended, the process is done in accordance with the following sequence.That is,

1) the controller 220 issues a command to the objective lens actuatordriving circuit 218 to disable the track loop;

2) the controller 220 issues a command to the objective lens actuatordriving circuit 218 to disable the focus loop;

3) the controller 220 issues a command to therecording/reproduction/erasure control waveform generation circuit 206to stop emission of the semiconductor laser element; and

4) the controller 220 informs the spindle motor driving circuit 215 ofzero reference rotational speed.

5. Flow of Recording Signal/Reproduction Signal to Information RecordingMedium

5-1. Signal Format Recorded on Information Recording Medium 9

In order to meet requirements:

-   -   of correcting recording information errors caused by defects on        the information recording medium 9;    -   of simplifying a reproduction processing circuit by setting zero        DC components of a reproduction signal; and    -   of recording information at highest possible density on the        information recording medium 9 for a signal to be recorded on        the information recording medium 9, the information        recording/reproduction apparatus (physical system block)        performs “addition of an error correction function” and “signal        conversion of recording information (signal        modulation/demodulation)”, as shown in FIG. 6.        5-2. Flow of Signal Upon Recording        5-2-1. ECC (Error Correction Code) Appending Process

Information to be recorded on the information recording medium 9 isinput to a data input/output interface 222 as recording signal d in theform of a raw signal. This recording signal d is directly recorded inthe semiconductor memory 219, and then undergoes an ECC appendingprocess in an ECC encoding circuit 208, as will be described later.

Upon completion of appending of inner-code PI and outer-code PO, the ECCencoding circuit 208 reads data for one sector from the semiconductormemory 219, and transfers the read data to a modulation circuit 207.

5-2-2. Signal Modulation

In order to make a DC component (DSV: Digital Sum Value) of areproduction signal approach zero, and to record information on theinformation recording medium 9 at high density, signal modulation asconversion of a signal format is done in the modulation circuit 207. Themodulation circuit 207 and a demodulation circuit 210 include aconversion table indicating the relationship between a source signal andmodulated signal. The signal transferred from the ECC encoding circuit208 is segmented into data each consisting of a plurality of bits inaccordance with a modulation scheme, and the segmented data is convertedinto other signals (codes) by looking up the conversion table. Forexample, when 8/16 modulation (RLL (2, 10) code) is used as themodulation scheme, two different types of conversion tables are present,and the conversion table to be looked up is switched as needed to makethe DC component (DSV) after modulation approach zero.

5-3. Flow of Signal Upon Reproduction

5-3-1. Binarization/PLL Circuit

As described in “signal detection by optical head 202”, a change in theamount of light reflected by the light reflection film or lightreflective recording film of the information recording medium 9 isdetected to reproduce a signal on the information recording medium 9. Asignal obtained by the amplifier 213 has an analog waveform. Thebinarization circuit 212 converts that signal into a binary digitalsignal consisting of “1” and “0” using a comparator.

From the reproduction signal obtained by the binarization circuit, thePLL circuit 211 extracts a reference signal upon reproducinginformation. The PLL circuit 211 incorporates a variable frequencyoscillator. The frequency and phase of a pulse signal (reference clock)output from the oscillator are compared with those of the output signalfrom the binarization circuit 212, and the comparison results are fedback to the oscillator output.

5-3-2. Signal Demodulation

The demodulation circuit 210 incorporates a conversion table indicatingthe relationship between modulated and demodulated signals. A modulatedsignal is restored to an original signal by looking up the conversiontable in synchronism with the reference clock obtained by the PLLcircuit 211. The restored (demodulated) signal is recorded in thesemiconductor memory 219.

5-3-3. Error Correction Process

An error correction circuit 209 detects any errors of a signal saved inthe semiconductor memory 219 using inner-code PI and outer-code PO, andsets pointer flags of error positions.

After that, the error correction circuit 209 corrects a signal at theerror positions in accordance with the error pointer flags while readingout the signal from the semiconductor memory 219, removes inner-code PIand outer-code PO, and transfers the signal to the data input/outputinterface 222.

A signal sent from the ECC encoding circuit 208 is output asreproduction signal c from the data input/output interface 222.

This concludes the detailed description of FIG. 6 is to end.

The format process sequence executed in the apparatus shown in FIG. 6will be explained below using the flowchart shown in FIG. 7. The formatprocess is implemented by the ECC encoding circuit 208 and controller220. FIG. 7 shows the sequence of the data conversion process (format)based on method 1 shown in FIGS. 1 to 3.

Step 1) A plurality of pieces of physical sector information 4-0 to 4-31are set (segmented into main data in units of 2048 bytes) incorrespondence with the size of a plurality of pieces of logical sectorinformation 3-0 to 3-31. User data to be recorded is handled in units of2048 bytes.

Step 2) 2068-byte sector data is generated from 2048-byte main data,16-byte auxiliary data, and a 4-byte error detection code (EDC).

As shown in FIG. 8, the 16-byte auxiliary data contains 4-byte data IDdata (PID), a 2-byte error detection code (IED) for the data ID, and10-byte reserve data (RSV). The PID records a sector number used toidentify a data sector, and sector information used to identify thecontents of the data sector. The IED is used to detect any errorsgenerated in the PID portion. The RSV is used to record other kinds ofauxiliary information (e.g., copyright management information). The EDCis used to detect any errors generated in 2064-byte main data andauxiliary data. The data sectors are arranged in a 188 (columns)×11(rows) matrix, as shown in FIG. 8.

Step 3) Scramble data is added to 2048-byte main data of each sectordata.

Step 4) The rows of the sector data shown in FIG. 8 are re-arrangeddepending on whether the sector number is even or odd, as shown in FIG.9. Numerals in FIG. 9 indicate row numbers in the sector data. Also, asshown in FIG. 9, re-arrangement types α and β are available.

Step 5) A sector block is generated by vertically stacking 32 continuousdata sectors, which are re-arranged depending on their sector numbers.The data sectors which are vertically stacked are arranged in a 376(columns)×176 (rows) matrix, as shown in FIG. 10.

Step 6) The sector block is horizontally segmented into two blocks toencode error correction codes. The 188 (columns)×176 (rows) blocks aftersegmentation undergo encoding in the column direction to generateouter-code parity (PO) data for 16 rows. The outer code uses a REEDSolomon code of RS(192, 176, 17). Subsequently, inner-code encoding isdone in the row direction to generate inner-code parity data (PI) for 12columns. The inner code uses a REED Solomon code of RS(200, 188, 13).ECC blocks containing parity data generated based on the inner and outercodes are as shown in FIG. 11.

Step 7) The ECC blocks undergo row interleave to distribute 16 right andleft rows of PO data into the blocks. Thirty-two rows (=16×2) of PO dataare distributed row by row to sectors. At this time, PO rows of the leftblock are inserted after the lowermost row of only five odd rows, and POrows of the right block are inserted after the lowermost row of onlyfive even rows. FIG. 3 shows the ECC blocks after row interleave.

Step 8) Physical sector data is completed. FIG. 12 shows the completedphysical sector data (=physical sector data blocks).

Step 9) A zigzag recording matrix is set.

Step 10) A modulation process is executed. If a bit sequence of data tobe recorded is directly recorded on the medium, the characteristicfeature of the recording data sequence does not match the recordingcharacteristics of the medium, and efficient recording cannot be done.In consideration of the recording characteristics of the medium, a datapattern is converted according to a predetermined conversion rule. Forexample, the modulation scheme includes an 8/16 modulation scheme forconverting 1-byte data into a 16-bit pattern, an 8/12 modulation schemefor converting 1-byte data into a 1.5-byte pattern, a 12/18 modulationscheme for converting 12-bit data into an 18-bit pattern, and the like.Any one of these schemes comprises a plurality of conversion tables anda logic circuit for selecting the conversion table.

Especially, since the 12/18 modulation scheme that converts 1.5-bytedata has a characteristic of expanding an error at one position to 1.5bytes, it is effective for the process executed in step 9 to distributeerrors upon reproduction.

Via steps 1 to 10, zigzag recording according to the setup in step 9 isdone. Zigzag recording will be described in detail below. The contentsof the physical sector data structure shown in FIG. 12 are segmentedfurther finely. Assume that the fine segmentation size is 1 byte, asshown in, e.g., FIG. 13. However, the present invention is not limitedto such specific segmentation unit length, and for example, a 2- or4-byte unit may be used. Data are selected and extracted across rows forrespective segmentation units, and are recorded on the physical sectorarea 9 a on the optical disk (information recording medium 9) inaccordance with the order they are selected and extracted. One physicalsector data is recorded on one physical sector area 9 a.

For example, as shown in FIG. 13, two upper and lower rows are paired,data in these upper and lower rows is extracted alternately (in a zigzagpattern) for respective segmentation units, and upon completion of onecycle of data extraction in a single column, unextracted data in thesepairs of rows is alternately fetched and recorded on the physical sectorarea 9 a on the optical disk (information recording medium 9).

In this case, the format method for method 1 has been mainly explained.However, the process in step 9 is also effective for method 2.Especially, in method 2, since neighboring rows belong to the differentECC blocks 7-0 and 7-1, as shown in FIGS. 4 and 5, if data is arrangedacross rows, data distribution across the ECC blocks 7-0 and 7-1 isattained. Hence, error distribution can be attained at a level finerthan the interleave process across the ECC blocks 7-0 and 7-1 forrespective rows.

In FIG. 13, data is extracted in a zigzag pattern from a pair of rows.However, the present invention is not limited to this. For example, datamay be sequentially extracted across three rows, or data may be selectedand extracted for respective segmentation units across all six rows, andmay be re-arranged and recorded on the physical sector area 9 a on theoptical disk (information recording medium 9).

As another recording method, data of different ECC blocks every rows maybe alternately recorded for several bytes, e.g., 1 byte.

Also, recording of data for one row in an order it is arranged does notdisturb the basic feature of the present invention.

Furthermore, a physical sector information portion may be re-arranged inany stage before step 6 so that auxiliary information containing atleast an ID continuously appears on a recorded data sequence inaccordance with the data recording order in step 9.

The information recording medium on which physical sector data isrecorded in this way is reproduced by the informationrecording/reproduction apparatus shown in FIG. 6. That is, physicalsector data is read out from a predetermined number of (32) physicalsector areas 9 a, n (2) ECC blocks are generated from the readoutphysical sector data, sector data is generated and reproduced from theECC blocks via an error correction process. The physical sector data isread out by the optical head. The sector data is reproduced by the errorcorrection circuit 209.

More specifically, by utilizing a process opposite to that forgenerating a predetermined number of physical sector data from n ECCblocks, n ECC blocks are generated from the predetermined number ofphysical sector data items read out from the predetermined number ofphysical sector areas 9 a. That is, two ECC blocks shown in FIG. 3 aregenerated from the physical sector data shown in FIG. 12. Subsequently,by utilizing a process opposite to that for generating ECC blocks afterrow interleave from those before row interleave, the n generated ECCblocks are restored to n ECC blocks before row interleave. That is, n(2) ECC blocks shown in FIG. 3 are restored to n ECC blocks shown inFIG. 11. At this time, an error correction process is executed usingouter- and inner-code parity data appended to the ECC blocks. Byutilizing a process opposite to that for generating ECC blocks fromsector blocks, the ECC blocks are restored to sector blocks. That is,outer- and inner-code parity data is removed from the ECC blocks shownin FIG. 11 to generate sector blocks shown in FIG. 10. Then, byutilizing a process opposite to that for generating sector blocks fromsector data, sector data is generated from the sector blocks. That is,sector data shown in FIG. 9 is generated from the sector blocks shown inFIG. 10. Since the generated sector data is in the re-arranged state, itis restored to an original arrangement upon reproduction.

Note that the physical sector data has a data structure in which thedata ID is arranged at the head of the data, and a data line formed byonly a portion of outer-code parity data is arranged as the final line.Hence, the information recording/reproduction apparatus shown in FIG. 6can reproduce the data ID by reading out the head data of the physicalsector data. Each physical sector area records data alternatelyextracted from different data lines in the physical sector data in turn(zigzag recording). Hence, the information recording/reproductionapparatus reproduces each physical sector area under the condition thatdata alternately extracted from different data lines is recorded.

FIG. 14 shows another embodiment of the data structure in physicalsector data in method 1. As shown in FIG. 14, data structures (A) to (C)are available, and are application examples which can be basicallygenerated via the aforementioned steps.

The format process for case (C) in FIG. 14, i.e., a case wherein onesector is formed of an even number of rows, will be explained belowusing the flowchart shown in FIG. 7 again.

The process to be described below is executed in the ECC encodingcircuit 208 shown in FIG. 6, and detailed control is made by thecontroller 220.

Step 1) A plurality of pieces of physical sector information 4-0 to 4-31are set (segmented into main data in units of 2048 bytes) incorrespondence with the size of a plurality of pieces of logical sectorinformation 3-0 to 3-31. User data to be recorded is handled in units of2048 bytes.

Step 2) 2064-byte sector data is generated from 2048-byte main data,12-byte auxiliary data, and a 4-byte error detection code (EDC). Asshown in FIG. 16, the 12-byte auxiliary data contains 4-byte data IDdata (PID), a 2-byte error detection code (IED) for the data ID, and6-byte reserve data (RSV). The sector data is arranged in a 172(columns)×12 (rows) matrix, as shown in FIG. 16.

Step 3) Scramble data is added to 2048-byte main data of each sectordata.

Step 4) The rows of the sector data shown in FIG. 16 are re-arrangeddepending on whether the sector number is even or odd, as shown in FIG.17. Numerals in FIG. 17 indicate row numbers in the sector data. Also,as shown in FIG. 17, re-arrangement types α and β are available.

Step 5) A sector block is generated by vertically stacking 32 continuousdata sectors, which are re-arranged depending on their sector numbers.The sectors are which are vertically stacked are arranged in a 344(columns)×192 (rows) matrix, as shown in FIG. 18.

Step 6) The sector block is horizontally segmented into two blocks toencode error correction codes. The 172 (columns)×192 (rows) blocks aftersegmentation undergo encoding in the column direction to generateouter-code parity (PO) data for 16 rows. The outer code uses a REEDSolomon code of RS(208, 192, 17). Subsequently, inner-code encoding isdone in the row direction to generate inner-code parity data (PI) for 12columns. The inner code uses a REED Solomon code of RS(184, 172, 13).ECC blocks containing parity data generated based on the inner and outercodes are as shown in FIG. 19.

Step 7) The ECC blocks undergo row interleave to distribute 16 right andleft rows of PO data into the blocks. Thirty-two rows (=16×2) of PO dataare distributed row by row to sectors. As the distribution destinationsof PO data, this data is inserted after the lowermost row of evensectors in the left block, and after the lowermost row of odd sectors inthe right block. FIG. 15 shows the ECC blocks after row interleave.

Step 8) Physical sector data is completed. FIG. 20 shows the completedphysical sector data.

Step 9) In this case, the setup of the zigzag recording matrix isomitted. This is because two different physical sector data items areinvolved at the lowermost row of the physical sector data (see FIG. 15).If the zigzag recording matrix is set in this case, two differentphysical sectors are mixed together in one physical sector area.

Step 10) A modulation process is executed. If a bit sequence of data tobe recorded is directly recorded on the medium, the characteristicfeature of the recording data sequence does not match the recordingcharacteristics of the medium, and efficient recording cannot be done.In consideration of the recording characteristics of the medium, a datapattern is converted according to a predetermined conversion rule.

The information recording medium on which physical sector data isrecorded in this way is reproduced by the informationrecording/reproduction apparatus shown in FIG. 6. That is, physicalsector data is read out from a predetermined number of (32) physicalsector areas 9 a, n (2) ECC blocks are generated from the readoutphysical sector data, sector data is generated and reproduced from theECC blocks via an error correction process.

More specifically, by utilizing a process opposite to that forgenerating a predetermined number of physical sector data items from nECC blocks, n ECC blocks are generated from the predetermined number ofphysical sector data items read out from the predetermined number ofphysical sector areas 9 a. That is, two ECC blocks shown in FIG. 15 aregenerated from the physical sector data shown in FIG. 20. Subsequently,by utilizing a process opposite to that for generating ECC blocks afterrow interleave from those before row interleave, the n generated ECCblocks are restored to n ECC blocks before row interleave. That is, n(2) ECC blocks shown in FIG. 15 are restored to n ECC blocks shown inFIG. 19. At this time, an error correction process is executed usingouter- and inner-code parity data appended to the ECC blocks. Byutilizing a process opposite to that for generating ECC blocks fromsector blocks, the ECC blocks are restored to sector blocks. That is,outer- and inner-code parity data is removed from the ECC blocks shownin FIG. 19 to generate sector blocks shown in FIG. 18. Then, byutilizing a process opposite to that for generating sector blocks fromsector data, sector data is generated from the sector blocks. That is,sector data shown in FIG. 17 is generated from the sector blocks shownin FIG. 18. Since the generated sector data is in the re-arranged state,it is restored to an original arrangement upon reproduction.

Note that the physical sector data has a data structure in which thedata ID is arranged at the head of the data, and a data line formed byonly a portion of outer-code parity data is arranged as the final line.Hence, the information recording/reproduction apparatus shown in FIG. 6can reproduce the data ID by reading out the head data of the physicalsector data.

Points of the present invention described above will be summarizedbelow.

(1) One physical sector is segmented into rows including PI, and rowdata is assigned to a plurality of ECC blocks.

(2) In the data arrangement of all physical sectors, the data ID isalways arranged at the head position. This structure matches the dataarrangement in physical sectors of the existing DVD. In this manner,since the data arrangement in an important portion in each physicalsector matches that of the existing DVD standards, the access controland sector address detection/confirmation processes in a reproductionapparatus or recording/reproduction apparatus having compatiblefunctions between the existing DVD and next-generation DVD can becommonly used, thus simplifying control in the apparatus.

(3) All physical sectors have equal sizes.

(4) “2 ECC blocks=32 physical sectors” is set as a basic unit incorrespondence with the SOBU size, and all data in 32 physical sectorsis assigned to two ECC blocks in the basic unit.

(5) Physical sector information matches logical sector information. Thecontents of one physical sector data are segmented into rows eachincluding PI data, row data is assigned in turn to n (n≧2) ECC blocks,and the total of the number of rows each including PI in one physicalsector data and the number of PO rows is an integer multiple of n.

(6) All pieces of information in one logical sector are contained indata in a single ECC block.

(7) Data in rows assigned to different ECC blocks in a single physicalsector is selected in turn and is recorded on the optical disk.

The arrangements and effects of the information recording medium,information recording apparatus, and information reproduction apparatusof the present invention will be described in detail below.

<1>First to Fifth Data Units are Defined as Follows.

A minimum unit recorded on a medium from which information can bereproduced or on which information can be recorded is defined as a firstdata unit (physical sector). A second data unit (a group of n ECCblocks) including the first data unit is defined. A third data unit (ECCblock data) which is included in the second data unit and forms an ECCblock that forms a REED Solomon product code is defined. The second dataunit includes n (n is a positive number equal to or greater than 2)independent third data units having equal data sizes. A fourth data unitwhich is included in the third data unit and forms one row as a dataarrangement appended with PI (inner-code parity) data is defined. Afifth data unit (PO for one row) which forms PO (outer-code parity) datain the third data unit and is segmented to be equal to the size (rowsize) of the fourth data unit is defined.

The first data unit is formed by a set of fourth and fifth data units,the total of the number of fourth data units (the number of rowscontaining PI) and the number of fifth data units (the number of POrows) is an integer multiple of n, and a data structure in which data ofthe fourth data units is always arranged at specific positions in thefirst data unit and a data ID containing address information is alwaysarranged at a specific position in the fourth data unit is generated.

The information recording medium of the present invention comprises aphysical sector area on which data with the aforementioned datastructure is recorded. The information recording apparatus and method ofthe present invention generate data with such a data structure, andrecord the data with the data structure on the information recordingmedium. Furthermore, the information reproduction apparatus and methodof the present invention reproduce the information recording medium onwhich the data with such a data structure is recorded.

The relationship between the aforementioned data units is as follows.

second data unit ⊃ first data unit ⊃ fourth data unit (n × ECC block)(physical sector) (row including PI) second data unit ⊃ Third data unit⊃ fourth data unit (n × ECC block) (ECC block) (row including PI) seconddata unit ⊃ Third data unit ⊃ fifth data unit (n × ECC block) (ECCblock) (row including PO)

The points of the present invention are as follows.

1) Data in one physical sector is segmented into rows, and row data isassigned to a plurality of ECC blocks.

2) A data ID is arranged at the head position in the physical sector,and PO data for one row is arranged in a row other than the first row.

3) The sum of the number of rows including PI and the number of PO rowsis an integer multiple of the number of corresponding ECC blocks.

The effects of the present invention are as follows.

1) Since the physical sector information size is the same as that in theexisting DVD (2048 bytes), full compatibility between the standardcontents of the logical layer and application layer of the existing DVDcan be assured, and existing DVD data can be effectively used byexchange and mixed storage of data recorded on existing DVDs ispossible.

2) Since n third data units are included in the second data unit, andphysical sector data (first data unit) is interleaved and arranged indifferent ECC blocks (third data units) for respective rows (fourth dataunits), an error-correctable burst error length can be improvedapproximately to n times. Hence, the present invention can relativelyeasily improve the error-correctable burst error length greatly withoutconsiderably lowering the main data information encoding efficiencycompared to the existing DVD standards.

3) The effect of a perfect product code formed by appending inner-code(PI) data in the horizontal direction and outer-code (PO) data in thevertical direction is as follows.

-   -   Since inner-code correction for outer-code parity data and        outer-code correction for inner-code parity data can be done,        correction performance can be improved by repeating correction        using inner and outer code data for all recorded data.    -   In combination with recording interleave, both distribution of        successive errors to inner-code data and perfection of a product        code that allows repetitive correction can be achieved.    -   Upon examining a method of “appending inner-code data obliquely        for the purpose of distributing successive errors” for the        purpose of comparison so as to obtain the effect of “the perfect        product code formed by appending inner-code (PI) data in the        horizontal direction and outer-code (PO) data in the vertical        direction”, perfection of the product code is impaired, and        correction performance cannot be improved by repeating        correction using inner- and outer-code data in such a case.

4) Except for interleave between a plurality of ECC blocks, datacorrespondence in the ECC blocks and physical sector data matches thatof the existing DVD standards:

-   -   correspondence between physical sector data and ECC block data        for respective rows including PI; and    -   interleaved arrangement of PO in ECC blocks to respective        physical sectors.

In this manner, some of the ECC block generation process (generation ofPI and PO, and the like) and error correction processes in areproduction apparatus or recording/reproduction apparatus havingcompatible functions between the existing DVD and next-generation DVDcan be used common to those used upon using an existing DVD disk(medium), and the processing routines and circuits of the reproductionapparatus or recording/reproduction apparatus having compatiblefunctions between existing DVDs and next-generation DVD can besimplified.

5) Since a data ID is arranged at the head of physical sector data as inthe existing DVD standards, the access control and sector addressdetection/confirmation processes in a reproduction apparatus orrecording/reproduction apparatus having compatible functions betweenexisting DVDs and next-generation DVDs can be commonly used, thussimplifying control in the apparatus.

6) Since the total of the number of rows including PI (the number offourth data units) and the number of PO rows (the number of fifth dataunits) included in the physical sector (first data unit) is an integermultiple of n, all data contained in one physical sector can beuniformly distributed (interleaved and arranged) in all correspondingECC blocks. Since all data can be evenly arranged in the ECC blocks, aninterleave process to the ECC blocks can be facilitated, and equalerror-correctable burst error lengths can be obtained independently ofthe positions on the optical disk, thus preventing adverse influences ofburst errors on reproduced information. That is, since an interleaveprocess is made to alternately record n product code data items onrespective rows, uniform burst error correction performance can beobtained. Hence, there is no locally weak burst error correctionperformance portion. Even when an interleave process for alternatelyarranging data is done, all the sectors can have equal sector lengths.

7) All the physical sectors have the same number of PO data items tohave equal physical sector sizes, and the following merits can beobtained.

In the prior art, in order to interleave a plurality of product codesand to distribute outer-code parity data in respective rows, outer-codeparity rows must be inserted in a plurality of sectors. Hence, a set ofa plurality of sectors must be recorded, or two different types ofsectors, i.e., sectors with and without parity data must be prepared.

According to the present invention, a rewrite can be made for eachsector. Especially, since an exchange process of defective sectors canbe done for respective sectors, the reserve sector size required for theexchange process can be reduced. Also, since the area, use of which isdisabled due to defects, can be reduced, the disk use efficiency can beimproved. Also, as sector identification data (ID) to be assigned torespective sectors can be recorded at equal intervals in recording data,the ID can be easily detected and reproduced.

In the invention described above, for example, n=2 is set. Incorrespondence with the SOBU size, “2 ECC blocks=32 physical sectors” isset as a basic unit, and all data in 32 physical sectors is assigned to2 ECC blocks in the basic unit to assure full compatibility with thestream standards. Also, the recording/reproduction process of a datarecording apparatus complying with the stream standards can besimplified.

<2>Furthermore, a Sixth Data Unit is Defined as Follows.

A sixth data unit (e.g., byte unit) obtained by further segmenting thefourth data unit (row) is defined. Since “fifth data unit=PO for onerow” has already been defined, “sixth data unit=recording interleaveunit across rows” is defined to avoid confusion.

The information recording medium of the present invention comprises aphysical sector area where sixth data units selected in turn fromdifferent fourth data units are recorded. The information recordingapparatus and method of the present invention select sixth data units inturn from different fourth data units, and record them on the physicalsector area of the information recording medium. The informationreproduction apparatus and method of the present invention reproduce thephysical sector area on which sixth data units selected in turn fromdifferent fourth data units are recorded.

The relationship between the aforementioned data units is as follows.

fourth data unit ⊃ sixth data unit (row including PI) (byte unit)

The point of the aforementioned invention is as follows.

Errors can be distributed by recording interleave (zigzag recording)among rows in a single physical sector.

The effects of the present invention are as follows.

Conventionally, recording is done in the same direction as inner-codedata. If successive data items have error correlation, a run of aplurality of bytes may readily cause errors at the same time, and it ishighly likely to disable correction of inner-code data. As a result, theerror correction performance is lowered considerably compared to a casewherein random errors are assumed. When the entire product code isobliquely recorded to distribute errors, a plurality of sectors maysimultaneously cause errors.

The error characteristics of reproduced data have error correlation insuccessively recorded data items due to the influence of dust or thelike. If error correlation is present, successive errors readily occurcompared to a case wherein it is assumed that errors occur randomly. Inorder to distribute errors that occur successively to differentinner-code data, the recording direction is set in a zigzag pattern withrespect to the direction of inner-code data. As a result, since thenumber of correctable inner-code data items increases, the errorcorrection performance can be improved. Since the zigzag pattern of therecording direction is limited to the range of one sector, successiveerrors never spread to a plurality of sectors. Hence, a plurality ofsectors can be avoided from causing errors due to serious errors.

<3>Moreover, Physical Sector Information and Logical Sector Informationare Defined as Follows.

User information recorded in a physical sector that forms the first dataunit is defined as physical sector information. The minimum unit of userinformation transferred in a data recording apparatus or datareproduction apparatus, or the minimum unit of user informationtransferred in the data recording apparatus or between the datareproduction apparatus and external device is defined as logical sectorinformation.

The information recording medium of the present invention comprises aphysical sector area that records data which is generated so that thecontents of the physical sector information match those of the logicalsector information. The information recording apparatus of the presentinvention generates and records data so that the contents of thephysical sector information match those of the logical sectorinformation. The information reproduction apparatus and method of thepresent invention reproduce the physical sector area that records datawhich is generated so that the contents of the physical sectorinformation match those of the logical sector information. In thismanner, the physical sector information can match the logical sectorinformation.

The effects of the aforementioned invention are as follows.

1) Data access can be made for respective logical sectors. When theerror rate of a reproduced signal from the optical disk is low, anderror correction of respective rows in the physical sector can be madeusing only PI information, error-free (accurate) physical sectorinformation can be read out without using PO information. Hence, whenECC blocks are formed so that logical sector information matchesphysical sector information as in the present invention, if the errorrate of a reproduced signal from the optical disk is low, one logicalsector information can be read out by only reproducing one physicalsector data from the optical disk without using any PO information, thusallowing very easy data access.

In the present invention, a data ID containing sector addressinformation is arranged at the head position in each physical sectordata item. In general, this data ID is used to access data recorded onthe optical disk. According to the present invention, since the contentsof the logical sector information match those of the physical sectorinformation, logical sector information can be recorded in this data ID.Hence, as logical sector address information in physical sector data canbe directly accessed to access the logical sector position designated bythe application or logical layer, the data access time can be greatlyshortened.

2) According to the present invention, data continuity can be easilyassured. In the format of the application standards, AV information andstream information are successively recorded in the order of logicalsector addresses. In the present invention, since the contents oflogical sector information match those of physical sector information,logical sector information can be recorded in the data ID. As a result,the order AV information and stream information to be recorded orreproduced in the order logical sector addresses are arranged matchesthe order of physical sector addresses, which is set in accordance withthe order physical sectors are arranged on the optical disk.Consequently, an unnecessary access process (track jump process) uponsuccessively recording or reproducing AV information and streaminformation on/from the optical disk can be greatly reduced, andcontinuity of AV information and stream information upon recording orreproduction can be easily assured.

3) According to the present invention, a defect process can be easilydone for respective sectors.

In the prior art, when a plurality of product codes is generated in aninteger number of sectors and the codes are interleaved, data of aplurality of sectors is mixed together upon recording. Hence, ifsuccessive burst errors have occurred due to defects, errors may besimultaneously produced in a plurality of sectors. Normally, since thepresence/absence of errors is finally checked for each sector, manysectors readily become defective at the same time. Also, since logicaladdresses are nonuniformly recorded, recorded data cannot be efficientlysearched.

According to the present invention, when uncorrectable errors haveoccurred due to defects, the residual errors can be prevented fromspreading after correction. As a result, the number of sectors thatcontain errors can be minimized. When a specific sector is searched forwhile reproducing data, the target position can be easily found due tocontinuity of sector numbers.

<4>Furthermore, the information recording medium of the presentinvention comprises a physical sector area that records data which isgenerated, so that the arrangement of at least some data in at least oneof a plurality of ECC blocks matches the contents of logical sectorinformation. The information recording apparatus and method of thepresent invention generate and record data so that the arrangement of atleast some data in at least one of a plurality of ECC blocks matches thecontents of the logical sector information. The information reproductionapparatus and method of the present invention reproduce the physicalsector area that records data which is generated, so that thearrangement of at least some data in at least one of a plurality of ECCblocks matches the contents of the logical sector information. In thisway, the contents of the logical sector information match the dataarrangement in an ECC block.

The effect of the aforementioned invention is as follows.

Processes until formation of ECC blocks for logical sector information,which is to be transferred in a data recording apparatus or between adata reproduction apparatus and external device, match those untilformation of ECC blocks in the existing DVD. Hence, some of the ECCblock generation processes (generation of PI and PO, and the like) anderror correction processes in a reproduction apparatus orrecording/reproduction apparatus having compatible functions betweenexisting DVDs and next-generation DVDs can be used common to those usedupon using an existing DVD disk, and the processing routines andcircuits of the reproduction apparatus or recording/reproductionapparatus having compatible functions between existing DVDs andnext-generation DVDs can be simplified.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

1. An information recording medium comprising: a management area wheremanagement information is recorded; and a plurality of physical sectorareas used to record a plurality sector data blocks, which are generatedby combining some data contained in a plurality of ECC blocks, whereinthe plurality of ECC blocks as a source of the plurality of physicalsector data blocks to be recorded in said plurality of physical sectorareas is generated via a predetermined process, and the predeterminedprocess generates the plurality of independent ECC blocks by: generatingsector data which contains a data ID and is formed of a first number ofbytes; generating re-arranged sector data by re-arranging data containedin the sector data to predetermined positions; generating a sector blockby combining a plurality of re-arranged sector data items; generating aplurality of segmented blocks by segmenting the sector block; generatingouter-code parity data by encoding data in a column direction, whichforms each segmented block; generating inner-code parity data byencoding data in a row direction, which forms each segmented block; andindividually appending the generated outer- and inner-code parity datato each segmented block.
 2. A medium according to claim 1, wherein eachphysical sector data block recorded on said physical sector area isformed of a set of data lines each of which is made up of a portion ofthe sector data and a portion of the inner-code parity data, andconsists of a second number of bytes, and data lines each of which ismade up of only a portion of the outer-code parity data and consists ofthe second number of bytes, and a total number of data lines of the setis an integer multiple of the number of ECC blocks.
 3. A mediumaccording to claim 1, wherein each physical sector data block recordedon said physical sector area contains the data ID, and has a datastructure in which the data ID is arranged at a specific position.
 4. Amedium according to claim 1, wherein each physical sector data blockrecorded on said physical sector area contains the data ID, and has adata structure in which the data ID is arranged at a head position, anda data line made up of only a portion of the outer-code parity data isarranged as a final line.
 5. A medium according to claim 1, whereinphysical sector information which indicates the physical sector datablock to be recorded on said physical sector area corresponds to logicalsector information which indicates the sector data.
 6. A mediumaccording to claim 5, wherein an arrangement of at least some data ofthe plurality of ECC blocks as a source of the plurality of sector datablocks to be recorded on said plurality of physical sector areascorresponds to logical sector information.
 7. An information recordingmedium comprising: management area where management information isrecorded; and a plurality of physical sector areas used to record aplurality of physical sector data blocks, which are generated bycombining some data contained in a plurality of ECC blocks, wherein saidphysical sector area is an area on which data alternately extracted fromdifferent data lines in the physical sector data block is recorded inturn.
 8. An information recording apparatus for recording information onan information recording medium, comprising: a generation sectorconfigured to generate a plurality of ECC blocks; and a recordingsection configured to generate a plurality of physical sector datablocks by combining some data contained in the plurality of ECC blocks,and to record the plurality of physical sector data blocks on aplurality of physical sector areas on the information recording medium,wherein said generation section generates the plurality of independentECC blocks by: generating sector data which contains a data ID and isformed of a first number of bytes; generating re-arranged sector data byre-arranging data contained in the sector data to predeterminedpositions; generating a sector block by combining a plurality ofre-arranged sector data items; generating a plurality of segmentedblocks by segmenting the sector block; generating outer-code parity databy encoding data in a column direction, which forms each segmentedblock; generating inner-code parity data by encoding data in a rowdirection, which forms each segmented block; and individually appendingthe generated outer- and inner-code parity data to each segmented block.9. An apparatus according to claim 8, wherein said recording sectionalternately extracts data from different data lines in the physicalsector data block, and records the extracted data in turn on thephysical sector data.
 10. An apparatus according to claim 8, whereinsaid recording section records the physical sector data block on thephysical sector area with physical sector information that indicates thephysical sector data block corresponding to logical sector informationthat indicates the sector data.
 11. An apparatus according to claim 10,wherein said recording section records the physical sector data block onthe physical sector area with an arrangement of at least some data ofthe plurality of ECC blocks corresponding to logical sector information.12. An information reproduction apparatus for reproducing an informationrecording medium which comprises a plurality of physical sector areas onwhich a plurality of physical sector data blocks generated by combiningsome data contained in a plurality of ECC blocks is recorded,comprising: a read-out section configured to read out the plurality ofphysical sector data blocks from the plurality of physical sector areason the information recording medium; and a reproduction sectionconfigured to reproduce data by generating the plurality of ECC blocksfrom the plurality of readout physical sector data blocks, wherein saidreproduction section generates the plurality of ECC blocks via apredetermined process, the predetermined process generates the pluralityof independent ECC blocks by: generating sector data which contains adata ID and is formed of a first number of bytes; generating re-arrangedsector data by re-arranged data contained in the sector data topredetermined positions; generating a sector block by combining aplurality of re-arranged sector data items; generating a plurality ofsegmented blocks by segmenting the sector block; generating outer-codeparity data by encoding data in a column direction, which forms eachsegmented block; generating inner-code parity data by encoding data in arow direction, which forms each segmented block; and individuallyappending the generated outer- and inner-code parity data to eachsegmented block, and said reproduction section reproduces the sectordata by utilizing the predetermined process.
 13. An apparatus accordingto claim 12, wherein the physical sector data block read out by saidread-out section is formed of a set of data lines each of which is madeup of a portion of the sector data and a portion of the inner-codeparity data, and consists of a second number of bytes, and data lineseach of which is made up of only a portion of the outer-code parity dataand consists of the second number of bytes, and a total number of datalines of the set is an integer multiple of the number of ECC blocks,each physical sector data block recorded on said physical sector areacontains the data ID, and has a data structure in which the data ID isarranged at a head position, and a data line made up of only a portionof the outer-code parity data is arranged as a final line, and saidreproduction section reproduces the data ID from the head position ofeach physical sector data block.
 14. An apparatus according to claim 13,wherein the physical sector area read out by said read-out sectionrecords data alternately extracted from different data lines in thephysical sector data block, and said reproduction section reproduces thephysical sector data block read out from the physical sector area undera condition that the data alternately extracted from the different datalines is recorded.